FAIR VALUE DISCLOSURES OF FINANCIAL ASSETS AND LIABILITIES - Schedule of Financial Instruments Carried at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	$ 4,153,615	$ 5,205,311
CMO
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	522,383	575,766
FNMA MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	3,294,230	4,245,684
FHLMC MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	123,017	145,528
GNMA MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	36,737	17,936
GSE agency notes
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	177,248	220,397
Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Other assets	163,229	5,153
Liabilities measured at fair value on a recurring basis:
Other liabilities	179,435	23,291
Assets measured at fair value on a nonrecurring basis:
Total assets	4,316,844	5,210,464
Fair Value, Measurements, Recurring | CMO
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	522,383	575,766
Fair Value, Measurements, Recurring | FNMA MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	3,294,230	4,245,684
Fair Value, Measurements, Recurring | FHLMC MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	123,017	145,528
Fair Value, Measurements, Recurring | GNMA MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	36,737	17,936
Fair Value, Measurements, Recurring | GSE agency notes
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	177,248	220,397
Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other real estate owned	840	2,320
Total assets	87,633	126,187
Fair Value, Measurements, Nonrecurring | Other investments
Assets measured at fair value on a nonrecurring basis:
Other investments	25,122	10,518
Fair Value, Measurements, Nonrecurring | Loans held for sale
Assets measured at fair value on a nonrecurring basis:
Loans, held for sale	61,671	113,349
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Other assets	0	0
Liabilities measured at fair value on a recurring basis:
Other liabilities	0	0
Assets measured at fair value on a nonrecurring basis:
Total assets	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring | CMO
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring | FNMA MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring | FHLMC MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring | GNMA MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring | GSE agency notes
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other real estate owned	0	0
Total assets	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Nonrecurring | Other investments
Assets measured at fair value on a nonrecurring basis:
Other investments	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Nonrecurring | Loans held for sale
Assets measured at fair value on a nonrecurring basis:
Loans, held for sale	0	0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Other assets	85	0
Liabilities measured at fair value on a recurring basis:
Other liabilities	17,579	20,252
Assets measured at fair value on a nonrecurring basis:
Total assets	85	0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | CMO
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	0	0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | FNMA MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	0	0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | FHLMC MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	0	0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | GNMA MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	0	0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | GSE agency notes
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	0	0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other real estate owned	840	2,320
Total assets	25,962	12,838
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring | Other investments
Assets measured at fair value on a nonrecurring basis:
Other investments	25,122	10,518
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring | Loans held for sale
Assets measured at fair value on a nonrecurring basis:
Loans, held for sale	0	0
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets measured at fair value on a recurring basis:
Other assets	163,144	5,153
Liabilities measured at fair value on a recurring basis:
Other liabilities	161,856	3,039
Assets measured at fair value on a nonrecurring basis:
Total assets	4,316,759	5,210,464
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | CMO
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	522,383	575,766
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | FNMA MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	3,294,230	4,245,684
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | FHLMC MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	123,017	145,528
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | GNMA MBS
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	36,737	17,936
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | GSE agency notes
Assets measured at fair value on a recurring basis:
Investment securities available-for-sale	177,248	220,397
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Nonrecurring
Assets measured at fair value on a nonrecurring basis:
Other real estate owned	0	0
Total assets	61,671	113,349
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Nonrecurring | Other investments
Assets measured at fair value on a nonrecurring basis:
Other investments	0	0
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Nonrecurring | Loans held for sale
Assets measured at fair value on a nonrecurring basis:
Loans, held for sale	$ 61,671	$ 113,349